Sweep conveyor for removal of grain and other materials from bins

ABSTRACT

A sweep conveyor extends along a bin floor between a sump pivot about which the conveyor rotates, and an outer end adjacent the bin wall. During the conveyor&#39;s orbit about the floor, flights at the conveyor bottom sweep across the floor toward the sump pivot, whereby bin material in front of the conveyor is swept into a sump. The conveyor is preferably made in modular sections connected end-to-end, whereby different sections are combined to construct conveyors having different lengths and capabilities. Some sections are preferably hinged together, allowing different sections to adopt different inclinations as they travel about a non-level floor. The flights are preferably provided on a belted chain riding on sprockets at opposite ends of the conveyor, and the chain is not supported by idler sprockets along its length, allowing the chain (and its flights) to sag under gravity so the flights ride along the bin floor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation under 35 USC §120 of U.S. patentapplication Ser. No. 13/654,774 filed Oct. 18, 2012 (now U.S. Pat. No.8,770,388), which in turn claims priority under 35 USC §119(e) to U.S.Provisional Patent Application 61/548,884 filed Oct. 19, 2011. Theentireties of these prior applications are incorporated by referenceherein.

FIELD OF THE INVENTION

This document concerns an invention relating generally to devices forremoving grain and other particulate and/or pulverulent materials fromstorage bins (silos, tanks, etc.), and more specifically to conveyorsused for such purposes.

BACKGROUND OF THE INVENTION

Sweep conveyors are often used to remove grain (wheat, corn, etc.) fromgrain bins, or otherwise remove loose material from other types of bins(e.g., wood pellets from storage silos, sand or aggregate from holdingpens, etc.) The conveyors move about the floor of the bin, typically byrotating about a pivot situated at the bin's center, and engage thematerial and convey it to a bin outlet, often a sump (pit) leading to achute or the like from which trucks, rail cars, etc. can receive thematerial. The conveyors thereby “sweep” the bin and remove the materialtherefrom. Sweep conveyors of this nature are typically of the screwauger type, wherein a rotating screw engages and conveys the material,or the flighted belt type, wherein flights on a moving belt engage andconvey the material (with the flights taking the form of paddles/fins,rakes/tines, or other protrusions which are typically designed toenhance transport of the material being swept). Examples of sweepconveyors of the auger type can be found in (for example) U.S. Pat. No.4,063,654 to Shivvers; U.S. Pat. No. 4,655,666 to Cantenot; U.S. Pat.No. 4,875,820 to Lepp el al.; U.S. Pat. No. 6,039,647 to Weikel; U.S.Pat. No. 6,095,742 to Campbell; U.S. Pat. No. 6,254,329 to Sukup et al.;U.S. Pat. No. 6,948,902 to Hanig; and U.S. Pat. No. 7,004,305 toSchaefer. Examples of sweep conveyors of the flighted belt type can befound in (for example) U.S. Pat. No. 3,229,665 to Baltz; U.S. Pat. No.3,338,636 to Chapman el al.; U.S. Pat. No. 3,443,700 to Cymara; U.S.Pat. No. 3,455,470 to Kanagy el al.; U.S. Pat. No. 3,472,357 toStrocker, U.S. Pat. No. 4,516,898 to Cantenot; U.S. Pat. No. 4,762,220to Lutke; and U.S. Pat. No. 6,499,930 to Dixon.

SUMMARY OF THE INVENTION

The invention, which is defined by the claims set forth at the end ofthis document, is directed to sweep conveyors which at least partiallyalleviate problems in the prior sweep conveyors, and/or which otherwiseimprove on the prior sweep conveyors in one or more respects. A basicunderstanding of some of the features of exemplary versions of theinvention can be attained from a review of the following brief summaryof the invention, with more details being provided elsewhere in thisdocument. To assist in the reader's understanding, the following summaryoccasionally makes reference to selected ones of the accompanyingdrawings (which are briefly reviewed in the “Brief Description of theDrawings” section following this Summary section of this document),though it should be understood that the noted features may be shown indrawings other than those noted. Since the following discussion ismerely a summary, it should be understood that more details regardingthe exemplary versions may be found in the Detailed Description setforth elsewhere in this document. The claims set forth at the end ofthis document then define the various versions of the invention in whichexclusive rights are secured.

The drawings (see particularly FIG. 1) illustrate an exemplary sweepconveyor 100 including a conveyor body 102 having a conveyor lengthextending between a conveyor sump pivot 104 and a conveyor outer end106. The conveyor body 102 rotates about the conveyor sump pivot 104 asit is driven about the floor of a bin (e.g., a grain bin, not shown),and the conveyor outer end 106 travels next to the wall of the bin(where a circular bin is used) as the conveyor body 102 is rotationallydriven. A tractor unit 108, here shown situated at the rear of theconveyor body 102, has wheels 110 which drive against the bin floor tourge the conveyor body 102 forwardly. (Rollers situated below theconveyor body 102, discussed below, can also help support the conveyorbody 102 during its travel about the bin.) During the orbit of the sweepconveyor 100 about the bin floor, flights 112 (here shown aspaddles/fins) situated at the bottom of the sweep conveyor 100 sweepacross the bin floor toward the conveyor sump pivot 104, whereby grainsituated within the bin in front of the sweep conveyor 100 is swept intoa sump 1000 (which, in a grain bin, is typically a pit having a passageto the outside of the bin). A “spider” 1002—a set of struts—typicallysupports a stanchion/pin 1004 or other structure above the sump 1000,with the conveyor sump pivot 104 being shown as a bearing rotationallyfit about this structure. (The sump 1000, spider 1002, and stanchion1004 are shown only in FIG. 1 for sake of simplicity.)

The flights 112 travel on an endless belt 114 (depicted as a chain belt)which rides on an inner wheel 116 at or adjacent to the conveyor sumppivot 104, and on an outer wheel 118 (FIG. 3) at or adjacent to theconveyor outer end 106 (with the wheels 116 and 118 being shown assprockets), with both wheels 116 and 118 being oriented to rotate aboutat least substantially vertical axes. A motor 120 (FIG. 2) drives theshaft 122 (FIG. 1) of the inner wheel 116 via an intervening gearbox124. As best seen in FIG. 3, each flight (paddle) 112 is preferablyformed of a plate 126 of flexible material (e.g., reinforced rubber)having a length extending horizontally between a flight inner end 128 atwhich the flight 112 is affixed to the belt 114, and an opposing flightouter end 130. Each flight 112 is affixed to the belt 114 via one ormore rigid legs 132 extending outwardly from the (chain) belt 114 nearthe middle of the flight's height, with the rigid leg(s) 132 extendingtoward the flight outer end 130 for a major portion of the length of theflight 112. As a result, each flight 112 is rigid for a major portion ofits length extending from the flight inner end 128, and is flexiblealong its flight outer end 130, as well as along its top and bottom. Theflights 112 can thereby yield somewhat if they scrape against the floorof the bin, and/or against surrounding portions of the conveyor body102, while at the same time having sufficient rigidity that they do notbuckle under heavy loads of grain.

A forward inner wall 134 (FIG. 3) is situated behind the flights 112near the bottom front of the conveyor body 102, and a rearward innerwall 136 (FIG. 4) is similarly situated inwardly from the flights 112 atthe bottom rear of the conveyor body 102. The belt 114 rides on theinner and outer wheels 116 and 118 about the forward and rearward innerwalls 134 and 136, with the space defined in front of the forward innerwall 134 defining a sweep area 138 (FIG. 1) where grain is engaged bythe flights 112 and swept toward the sump 1000. The space definedrearwardly of the rearward inner wall 136 defines a return area 140(FIG. 4) where the flights 112 leaving the sump 1000 travel toward theconveyor outer end 106 to reenter the sweep area 138. The return area140 is bounded by a rearward outer wall 142 (FIG. 2) spaced from therearward inner wall 136, such that the flights 112 traveling in thereturn area 140 have their flight outer ends 130 sweep closely adjacentto (and/or against) the rearward outer wall 142. Preferably, a majorportion of the return area 140 from the conveyor sump pivot 104 (FIG. 1)to a location near the conveyor outer end 106 is also bounded at itsbottom by a rear floor 144 (FIG. 5) extending between the rearward innerand outer walls 136 and 142 beneath the flights 112, thereby deterringgrain that failed to fall into the sump 1000 (FIG. 1) from beingredeposited onto the bin floor as the flights 112 travel through thereturn area 140. A roof 146 (FIG. 5) is also preferably provided over atleast the return area 140 for similar reasons.

Chutes 148 (FIG. 1) are defined in the top front of the conveyor body102 above the sweep area 138 such that grain atop the top front of theconveyor body 102 can fall into the chutes 148, and thereby into thesweep area 138 for removal. Each chute 148 preferably bears a grating150 which extends forwardly above the sweep area 138, with each grating150 being shown as a set of parallel spaced bars 152 which extendsforwardly above the sweep area 138 (with the spacing between the bars152 being such that grain can readily fall through the bars 152). Thegrating bars 152 have endplates 154 at their opposing ends so that thebars 152 can conveniently be installed and removed as a unit formaintenance of the sweep conveyor 100, e.g., to obtain top access to theflights 112 and belt 114. The gratings 150 allow the flights 112 to morespeedily remove material when the sweep conveyor 100 is driven intotaller piles of material, such as those near the perimeter of a grainbin away from the sump 1000, and/or at the mound of grain that can ariseat a location where grain is poured into a bin. The gratings 150 alsohelp to deter large clumps of material from entering the sweep area 138,at which point they can be swept to the sump 1000, where they may clogit. Instead, the bars 152 of the gratings 150 tend to break up suchclumps owing to the weight of the grain pressing such clumps against thebars 152, as well as owing to the vibration of the bars 152 duringoperation of the sweep conveyor 100. Beneficially, the gratings 150allow grain to pass through the height of the conveyor body 102,reducing the weight of the grain on the conveyor 100 when it restsbeneath a pile of grain, and allowing the grain to partially support theconveyor body 102. The gratings 150 additionally provide some degree ofsafety in case an operator is within a bin during operation of the sweepconveyor 100 (which is not recommended practice), as the bars 152 deteran operator's stepping into the sweep area 138. The illustrated barredconfiguration for the gratings 150 is preferred, as the bars 152 addstiffness to the conveyor length (particularly when oriented parallel tothe conveyor length).

The conveyor body 102 also preferably includes one or more flexible(e.g., reinforced rubber) flanges extending downwardly along theconveyor length below the conveyor body 102, whereby as the conveyorbody 102 travels along a floor, the flanges ride along the floor tofurther sweep and collect grain that was not driven into the sump 1000by the flights 112. Such “wiper” flanges preferably include flanges 156(FIG. 5) descending from the forward inner wall 134, i.e., at the rearside of the sweep area 138, as well as flanges 158 (FIG. 2) descendingfrom the rearward outer wall 142 at the conveyor outer end 106 (wherethe return area 140 lacks a floor at the exit of the return area 140).The flanges 156 and 158 are preferably mounted by sandwiching themagainst the rear side of the forward inner wall 134, and against therear side of the rearward outer wall 142, by elongated plates 160 (FIG.5) and 162 (FIG. 2) which are bolted or otherwise adjustably affixed tothese walls 134 and 142. Such an arrangement allows a flange 156/158 tobe raised or lowered as desired by loosening the plate 160/162,adjusting the height of the flange 156/158, and then tightening theplate toward the wall 134/142.

The conveyor body 102 is also preferably formed in modular body sectionswhich are adjacently arrayed along the conveyor length, with each bodysection including a portion of the sweep area 138 (adjacent a portion ofthe forward inner wall 134), and a portion of the return area 140(between a portion of the rearward inner wall 136 and a portion of therearward outer wall 142). Different types and numbers of sections canthen be combined to construct sweep conveyors having different lengthsand capabilities, and sections can also be easily removed for repair andreplacement. As seen in FIGS. 1-2, the sweep conveyor 100 includes fivebody sections: an inner body section 164 bearing the conveyor sump pivot104, inner wheel 116, gearbox 124, and motor 120; an outer body section166 at the conveyor outer end 106, which bears the outer wheel 118; andone longer (e.g., 5-8 ft.) intermediate body section 168 and a pair ofshorter (e.g., 2-4 ft.) intermediate body sections 170 a and 170 b(collectively 170), each of which bears the aforementioned bars 152.These intermediate body sections 168/170 may be provided in differentnumbers to construct sweep conveyors of different lengths, with a belt114 being sized to fit about the inner wheel 116 (FIG. 1) of the innerbody section 164 and the outer wheel 118 (FIG. 3) of the outer bodysection 166. An inner body section 164 with an appropriately-sized motor120 (FIG. 2) can be chosen to drive the belt 114. Different bodysections may also be specially configured to meet special objectives,depending on the application for which the sweep conveyor 100 is to beused. For example, in grain bin applications, grain near the binperimeter tends to clump at the bottom of the bin owing to condensationand possible water ingress into the bin. Thus, it can be beneficial toomit any rear floor 144 (FIG. 5) beneath the return area 140 of theouter body section 166 (see particularly FIG. 3), so that the flights112 in both the sweep and return areas 138 and 140 of the outer bodysection 166 can scrape at clumped material to better remove it from thebin.

While adjacent body sections can simply be bolted or otherwise affixedtogether, at least some of the adjacent body sections are preferablyhingedly connected such that they may pivot with respect to each otherin vertical planes (i.e., adjacent body sections can deviate from thehorizontal plane). This arrangement allows the conveyor body 102 to flexalong its length if different body sections encounter different floorheights. In FIGS. 2 and 4, a hinge 172 is situated between the shorterintermediate body sections 170 a and 170 b, such that the shorterintermediate body sections 170 a and 170 b in combination might beregarded as a hinged body section 170 which flexes along its length. Thehinge 172 includes a set of hinge plates 174 connected to the rearwardouter walls 142 of the body sections 170 a and 170 b outside the returnarea 140, as seen in FIGS. 2 and 4, with the hinge plates 174 beingpivotally pinned together; and a similar set of hinge plates 174connected to the forward inner walls 134 of the body sections betweenthe forward and rearward inner walls 134 and 136, as seen only in FIG.4, with the hinge plates 176 being pivotally pinned together. Thesehinge plates 174 are shown in the form of sets of ears extending fromeach of the shorter body sections 170 a and 170 b to rest in paralleladjacent relationship, with a pair of ears on each shorter body section170 a and 170 b receiving an ear of the other shorter body sectiontherebetween, and with a pin 176 extending between the ears to pivotallyfix them together. Away from the hinge 172, the shorter body sections170 a and 170 b have sufficient space between their adjacent ends thatthe hinge 172 allows (for example) as much as five degrees of variationof one of the body sections 170 a and 170 b with respect to the other.The hinge 172 may also (or alternatively) include lengths of flexiblebarrier material joined between the body sections 170 a and 170 b, withFIGS. 1-2 illustrating a rubber strip 178 which extends between theadjacent ends of the body sections 170 a and 170 b from their top rearsides to their top front sides (with plates 206, FIG. 2, and 154, FIG.1, sandwiching the strip 178 against the end of each body section 170 aand 170 b). The barrier material 178 helps avoid the passage of grainthrough the space between the adjacent ends of the body sections 170 aand 170 b, while at the same time also allowing pivoting between thebody sections 170 a and 170 b.

To allow adjustment of the tension of the belt 114 bearing the flights112, at least one of the body sections bearing one of the belt-carryingwheels bears a tensioner which carries one of the wheels thereon, andwhich is movable along the conveyor length to adjust the tension in thebelt 114. FIG. 4 illustrates a tensioner 180 formed as an elongatedrectangular box or beam fit between the forward and rearward inner walls134 and 136 of the outer body section 166, and having a tensioner wheelend 182 bearing the outer wheel 118, and an opposing tensioneradjustment end 184. A screw 186 extends between and engages thetensioner 180 and the outer body section 166 (at a threaded aperture ona bridge 188 extending between the forward and rearward inner walls 134and 136 of the outer body section 166). By turning the end of the screw186 (which can be accessed from the door 190 situated at the top rearside of the adjacent shorter intermediate body section 170 b), thetensioner 180 (and thus the outer wheel 118) is urged along the lengthof the outer body section 166, thereby allowing modification of thetension of the flight-bearing belt 114.

As best seen in FIGS. 2 and 4, the tractor unit 108 is shown situated ona tractor arm 192 extending from the rearward outer wall 142 of theouter body section 166, though the tractor unit 108 could be situated onother body sections instead (and/or additional tractor units 108 can besituated on other body sections). Preferably, at least one tractor unit108 is situated along the conveyor length at a location closer to theconveyor outer end 106 than the conveyor sump pivot 104, since tractorunits 108 situated closer to the conveyor outer end 106 can moreefficiently drive the conveyor body 102 forwardly. The tractor unit 108is preferably connected to the conveyor body 102 to pivot about an axisoriented at least substantially perpendicularly to the conveyor length,as by providing a bearing along the tractor arm 192. Such an arrangementbetter allows both wheels 110 of the tractor unit 108 to remain on (anddrive against) the bin floor when the floor is not level. To provide thetractor unit 108 with better traction on the floor, it may be weighted,with FIGS. 1-2 and 4 showing a set of weights 194 situated atop thetractor unit 108 (with these weights 194 being removable and replaceableso that a user may weight the tractor unit 108 as desired).

Further advantages, features, and objects of the invention will beapparent from the remainder of this document in conjunction with theassociated drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of an exemplary sweep conveyor 100 asdiscussed above, with the sweep conveyor 100 rotating about the conveyorsump pivot 104 on the bin floor (not shown), and with its flights 112sweeping inwardly toward the sump 1000 such that grain encounteredduring the travel of the conveyor 100 is swept into the sump 1000.

FIG. 2 is a rear perspective view of the sweep conveyor 100 shownwithout the sump 1000 of FIG. 1.

FIG. 3 is a front perspective view of the outer end 106 of the outerbody section 160 of the sweep conveyor 100 of FIGS. 1-2.

FIG. 4 is a simplified schematic top cross-sectional view of the sweepconveyor 100 of FIGS. 1-3 taken along a horizontal plane situatedapproximately halfway up the heights of the flights 112, butschematically illustrating the tractor unit 108 from its top (withoutsectioning).

FIG. 5 is a simplified schematic cross-sectional view of the longerintermediate body section 168 of the sweep conveyor 100 of FIGS. 1-3,taken along the vertical plane 5-5 illustrated in FIG. 4.

DETAILED DESCRIPTION OF PREFERRED VERSIONS OF THE INVENTION

Expanding on the discussion above, the conveyor body 102 will typicallyrest on the floor of a grain bin or the like, and will often be whollyor partially buried in grain poured atop it within the bin. The conveyorbody 102 is driven by the tractor unit 108 to rotate (in a clockwisedirection in FIG. 1) about the conveyor sump pivot 104. During suchrotation, the motor 120 (FIG. 2) drives the inner wheel 116 (FIG. 1),and thus the belt 114 and flights 112 thereon, so that the flights 112in the sweep area 138 are driven inwardly toward the sump 1000. Graincan enter the sweep area 138 both from the bottom front of the conveyorbody 102 (i.e., in front of the flights 112 as the conveyor body 102 isdriven forwardly by the tractor 108), and also by falling into thechutes 148 defined beneath the bars 152 in the intermediate bodysections 168, 170 a, and 170 b, to be swept by the flights 112 into thesump 1000. The flange 156 (FIG. 5) situated at the bottom of the forwardinner wall 134, and the flange 158 (FIGS. 2-3) at the rearward outerwall 142 of the outer body section 166, assist in collecting anyresidual grain that isn't swept by the flights 112. As the conveyor body102 travels about the bin floor, it can navigate over uneven orotherwise irregular areas of the floor (owing to settling, non-levelconcrete pouring, floor features such as aeration tunnels, etc.), andeffectively sweep grain despite such irregularities, owing to theflexibility in the perimeters of the flights 112, and owing to thepivotally-connected body sections 170 a and 170 b. The bottom edges ofthe flights 112 bend in a squeegee-like fashion as they run across thebin floor, and the flexure between the hinged intermediate body sections170 a and 170 b allows adjacent sections of the conveyor body 102 totilt with respect to each other along the conveyor length. The use ofone or more hinged body sections 170 (i.e., a pair of hingedly connectedbody sections 170 a and 170 b) is particularly useful to accommodatefloor irregularities: since a conveyor body 102 will typically beassembled to extend 30-70 feet in length (though lesser or greaterlengths are possible), a rigid conveyor body 102 might result in theflights 112 passing over low areas on the floor, thereby leaving grainbehind, and/or the portions of the conveyor body 102 might “hang up” onhigh areas and be unable to move. Moreover, the weight of the grain in afull bin could cause undesirable stress over a conveyor body 102 havinga rigid conveyor length. Beneficially, the sweep conveyor 100 depictedin the drawings has a very low center of gravity, which helps detertipping or twisting of the conveyor body 102 along its length when it isburied in grain, and/or when it encounters irregular grain loading alongits conveyor length.

At the inner body section 164, the motor 120 (FIG. 2) and/or gearbox 124are appropriately chosen to provide the desired output when driving theflights 112 (FIG. 1). The motor 120 is covered by a hinged shield 196 sothat when the sweep conveyor 100 is buried in grain, the motor 120 isless likely to overheat. The motor 120 is preferably a variablefrequency electric motor which is controlled to operate at anappropriate speed by a programmable logic control or other controller,though other types of motors can be used (e.g., hydraulic or othernon-electric motors may be useful where totally spark-free operation isdesirable, such as when the sweep conveyor 100 is used to sweepignitable powders, though “XP-rated”—i.e., explosion-proof—electricmotors will generally be suitable). Preferably, the controller monitorsthe speed and torque of the motor 120 and tractor unit(s) 108 to obtaina measure of grain removal, and adjusts the power supplied to each toattain a desired rate of removal. For example, if the output of themotor 120 indicates increasing torque and decreasing speed (indicatingthat the motor 120, and its associated belt 114 and flights 112, arebeginning to “strain” to achieve grain removal), the tractor unit(s) 108might be paused or slowed until the burden on the flights 112 decreases.As another example, if the output of the motor 120 is such that stallingof the flights 112 (e.g., from plugging of the sweep area 138 and/or thereturn area 140, FIG. 4) is indicated, the tractor unit(s) 108 may bestopped, and the controller may attempt to drive the motor 120 (andpossibly the tractor unit(s) 108) in reverse for a period to see if thestalling can be resolved. It is notable that the ability toindependently alter the speeds of the belt/flight motor 120 and thetractor unit(s) 108, and/or adjust the speed of one in at least partialdependence on the operating state of the other, avoids many of thedrawbacks that arise where the grain-conveying drive and thefloor-traveling drive of a sweep conveyor are always running together,as is common in prior sweep conveyors. For example, in many priorsweeps, when the grain-conveying drive encounters a large load of grain,it is necessary to use jacks or other lifts to lift the wheels of thefloor-traveling drive off the floor to slow or halt their drivingaction. Otherwise, the grain-conveying drive may overload as thefloor-traveling drive continues to push the sweep conveyor into thegrain before the grain-conveying drive adjusts to the load.

Additional sensors may supply feedback regarding the level of grainand/or grain flow in the sump 1000, the temperature of the motor 120,the position of the sweep conveyor 100 about the bin floor, and otherfactors. Ideally, the sweep conveyor 100 may be entirely monitored andcontrolled at a remote station outside the grain bin, so that a “zerobin entry” system is provided.

Within the inner body section 164, the shaft 122 (FIG. 1) of the innerwheel 116 is supported at its opposing ends by high-strength bearings todeter deflection of the shaft 122. While not depicted in the drawings,the rearward outer wall 142 (FIG. 2) adjacent the inner wheel 116(FIG. 1) preferably curves to closely follow the path followed by theflight outer ends 130 to better avoid a “dead area” where grain mightcollect. It is notable that the use of the inner and outer wheels 116and 118 to support the flight-bearing belt 114, without the use ofintermediate “idler” wheels, allows the belt 114 to sag somewhat (ifappropriately tensioned). As a result, the flights 112 can drag acrossthe floor in the sweep area 138, allowing more thorough removal ofgrain.

The longer intermediate body section 168, as best seen in FIG. 1 and inthe cross-sectional view of FIG. 5, has its forward inner wall 134continue upwardly at a slight angle to the peak of the longerintermediate body section 168, thereby defining a rear chute wall 198which directs any grain falling thereon through the bars 152 of thegrating 150 toward the sweep area 138 (shown occupied by a flight 112 inFIG. 5, as with the return area 140 between the rearward inner wall 136,the rearward outer wall 142, the rear floor 144, and the roof 146). Asloped conveyor body rear top wall 200 extends from the peak to therearward outer wall 142 to better direct grain avalanching over theconveyor body 102 toward the rear of the sweep conveyor 100. As notedpreviously, rollers can be situated at the bottom of the conveyor body102 to help support it during its travel about the bin, and one suchroller 202 is depicted within the space 204 between the forward andrearward inner walls 134 and 136. Rollers of this nature, which arepreferably made of steel, can be situated at the bottom of each conveyorsection between the forward and rearward inner walls 134 and 136, withthe rollers 202 being oriented to roll along planes oriented generallyperpendicular to the conveyor length. These rollers 202 preferably haveadjustable height, as by supporting their central shafts on screws (notshown), such that the clearance of the bottom of each conveyor sectionover the bin floor is adjustable. Typically, it is preferable to havethe rollers 202 support each conveyor section so that the section is asclose as possible to the bin floor, typically by no more than a quarterto a half an inch. FIG. 5 also depicts the aforementioned flexibleflange 156, which helps collect grain which is not swept out of thesweep area 138. The flange 156 is sandwiched against the rear side ofthe forward inner wall 134 by an elongated plate 160, with bolts (notshown) extending through the plate 160 and flange 156 to engage theforward inner wall 134.

The shorter intermediate body sections 170 a and 170 b are generallyconstructed similarly to the longer intermediate body section 168, savefor their shorter length, and save for the (optional) hinge 172connecting them. If a hinge 172 is included, it is preferably providedon both the rearward outer walls 142 of the adjacent body sectionsoutside the return area 140, as well as on the forward inner walls 134of the adjacent body sections between the forward and rearward innerwalls 134 and 136, as with the hinges 172 seen in FIG. 5. The barrierstrip 178 “sealing” the seam defined between the hingedly connected bodysections 170 a and 170 b is preferably formed of rubber or anotherelastomer, though a strong fabric (e.g., durable canvas) or othersuitably flexible material may be used instead. The strip 178 extendsupwardly across the rear top walls 200 of the shorter body sections 170a and 170 b (against which the strip 178 is sandwiched by the plates206) to extend over, and be folded about, the front side edges of theshorter body sections 170 a and 170 b. The barrier material 178 is thereheld in place by the gratings 150 of the shorter body sections, whoseendplates 154 sandwich the barrier material 178 against the abuttingwalls of the shorter body sections 170 a and 170 b. The strip 178 cantherefore be removed and replaced when needed by unbolting the plates206 from the rear top walls 200, and by unbolting the grating endplates154 from the walls.

The outer body section 166, which bears the outer wheel 118 carrying theflight-bearing belt 114, includes the aforementioned tensioner 180 foradjusting the tension of the belt 114 (e.g., for tightening the belt 114when it stretches after a period of use). As previously noted, thetensioner 180 is shown in FIG. 4 as a rectangular box closely andslidably fit within the space between the forward and rearward innerwalls 134 and 136 of the outer body section 166 (and between the floor144 and roof 146 of this space as well). The tensioner wheel end 182defines a yoke wherein the outer wheel 118 is rotatably mounted betweenbearings, and the opposing tensioner adjustment end 184 bears a threadedaperture which receives the screw 186. The end of the screw 186 is thenrotatably mounted in a bearing or the like on the bridge 188 extendingbetween the forward and rearward inner walls 134 and 136 of the outerbody section 166. A user may therefore access the end of the screw 186via the access door 190 at the rear top wall 200 of the adjacent shorterbody section 170 b, and turn the screw 186 to drive the tensioner 180(and thus the outer wheel 118) along the conveyor length to attain thedesired tension in the flight-bearing belt 114. (Such an access door190, or at least the aperture thereof, is preferably provided near oneor more ends of each body section 164, 166, 168, and 170 a/170 b toallow maintenance access to the interior of the body section, but thedoor may be welded shut—or its aperture simply omitted—where no suchaccess is needed.)

The tractor 108, which extends from the rear of the outer body section166 on the tractor arm 192, is preferably pivotable about the axis ofthe tractor arm 192 so that the tractor 108 can better accommodate floorunevenness. As seen in FIG. 5, the tractor arm 192 preferably does notextend perpendicularly from the conveyor length, or more precisely, theaxes of rotation of the wheels 110 do not extend parallel to theconveyor length, and are rather oriented at an angle to theperpendicular (or to the conveyor length), as this has been found toprovide better traction. A high-torque electric motor 208 is controlledby the controller for the sweep conveyor 100 to drive the wheels 110 ofthe tractor unit 108. The tractor arm 192 extends rearwardly from themotor 120 and wheels 110 to support the removable weights 194, which aredepicted as plates having U-shaped handles 210 at their ends. Theweights 194 are mounted on the tractor arm 192 by inserting legs 212extending from the tractor arm 192 into the U-shaped handles 210,thereby holding the weights 194 firmly in place on the tractor arm 192even when the tractor 108 drives forwardly when buried under grain.

The walls, ceilings, floors, etc. of the various body sections 164, 166,168, and 170 a/170 b are preferably made of metal sheets/panels, e.g.,0.1-0.5 inch thick hot-rolled steel, with flanges and other reinforcingstructures being formed to add strength along larger unsupported areas,or at areas experiencing greater stress.

Power is preferably supplied to the sweep conveyor 100 via linesextending upwardly within the stanchion 1004, and leading to the sweepconveyor 100 and its belt motor 120, tractor motor(s) 208, etc., viaappropriate rotary power transmission couplings (e.g., electrical sliprings, hydraulic rotating unions, etc.).

An exemplary sweep conveyor 100 is shown in the drawings and describedabove to illustrate a possible configuration and features of theinvention. However, sweep conveyors in accordance with the invention canbe presented in forms which differ significantly from the form of theexemplary sweep conveyor 100 shown in the drawings and described above,with different sizes, proportions, components, etc., and the functionsand operation of the sweep conveyor 100 can also vary from thosedescribed above. Following is a brief review of exemplary modificationsthat can be made.

While the function and operation of the sweep conveyor 100 is frequentlydescribed above in relation to removal of grain from a grain bin, thesweep conveyor 100 can be used for removal of other materials from othertypes of bins, e.g., removal of animal feed from feed storage tanks,removal of coal from coal cribs, etc.

The sweep conveyor 100 is described as rotating about a sump pivot 104on a bin floor, but with appropriate modification, it can sweep alongnon-rotary paths. For example, if the sump pivot 104 is removed and oneor more tractors 108 are installed to apply a driving force along theentire conveyor length, the sweep conveyor 100 can be made to sweepalong a linear path. To illustrate, the sweep conveyor 100 might beinstalled to rest parallel to a wall of a rectangular bin, with the endsof the conveyor length being configured to ride along rails mounted onthe adjacent walls of the bin, and the sweep conveyor 100 can be drivenalong the rails to sweep linearly across the floor of the bin.

As noted previously, the sweep conveyor 100 may include numbers, orders,and types of body sections other than those shown (e.g., more or fewerlonger and shorter intermediate body sections 168 and 170 a/170 b mightbe incorporated in the depicted sweep conveyor 100). Hinges 172 may beincorporated between body sections where desired, and need notnecessarily be provided only between shorter intermediate body sections170 a/170 b (though providing hinges 172 between adjacent shorterintermediate body sections 170 a/170 b is useful to generate a hingebody section 170 that can then be installed along the conveyor length asneeded). One or more tractors 108 may be provided on body sections otherthan the outer body section 166 to provide driving force as desired.

Body sections may also be configured significantly differently fromthose shown. As examples, they need not have a pentagonal peakedcross-section (as seen in FIG. 5), and could (for example) omit thesloped conveyor body rear top wall 200, and instead have a singleforwardly-sloping chute wall 198 extending from the rearward outer wall142 to the rearward inner wall 136. The external tractors 108 might beomitted, and the rollers at the bottom of the conveyor body 102 betweenthe forward inner wall 134 and the rearward inner wall 136 could bemotorized to drive the conveyor body 102 (though the external tractors108 are preferred).

The conveyor sump pivot 104 need not take the form of a bearing fitabout a stanchion 206, and could instead (for example) take the form ofa descending stanchion which fits into a bearing. While not depicted inthe drawings, it is useful to provide a relatively low-friction disc(e.g., of ultra-high molecular weight PET) between the bearing 104 andthe sump spider 1002, and/or a low-friction plate at the bottom of theinner body section 164, to reduce friction and possible metal-on-metalcontact between the inner body section 164 and the sump spider 1002.

The sump pivot 104 also need not be situated at an end of the conveyorlength: body sections may be situated on opposing sides of the innerbody section 164 (or more particularly on opposing sides of the conveyorsump pivot 104), such that the conveyor length straddles the sump 1000.In this case the flighted belt 114 might ride on the inner wheel 116 andtwo outer wheels 118, one at each end of the conveyor length. (Or themotor 120 and inner wheel 116 could be situated at one end of theconveyor length, and the outer wheel 118 could be situated across thesump 1000 at the opposite end of the conveyor length, perhaps with oneor more idler wheels 110 being situated at or near the sump 1000.) Onopposite sides of the sump pivot 104, the sweep and return areas 138 and140 would exchange locations so that the sweep area 138 at each side ofthe sump 1000 is always driven forwardly about the bin floor, with thereturn area 140 trailing. Such a sweep conveyor could, for example,extend across the entire diameter of a grain bin, and could beneficiallyremove grain from opposing sides of the grain bin at the same time,thereby avoiding the stresses on the bin walls that can arise fromunbalanced loading. An alternative to this arrangement is to simply taketwo independent sweep conveyors (such as two of the sweep conveyors 100as seen in FIGS. 1-2) and mount them about a common conveyor sump pivot104. A particularly preferred alternative version of the sweep conveyor100 has portions of its conveyor length on opposing sides of the sump1000, with a length extending the full radius of the grain bin on oneside of the sump 1000 (i.e., extending from the sump pivot 104 to thebin wall), and a length extending approximately half the radius of thegrain bin on the opposite side of the sump 1000. A single belt 114drives the flights 112 across the conveyor length, with the belt 114being driven by a single motor 120 situated on the shorter side of thesweep conveyor 100 (preferably on the outer body section situated at theend of the shorter side of the sweep conveyor 100). Such a sweepconveyor helps to avoid the aforementioned bin wall stresses owing tounbalanced unloading of the grain bin, while only requiring a motor 120of moderate power, size, and price. In contrast, a sweep conveyor 100extending the full diameter of the bin typically requires a moresignificant motor 120 to drive the belt 114 across the entire bindiameter.

While the belt 114 and inner and outer wheels 116 and 118 are depictedas a chain and sprockets, these could take different forms, e.g., thebelt 114 may assume the form of a band or cable, and the wheels 116 and118 may assume the form of rollers (for driving the band) or pulleys(for driving the cable).

A chute 148 (preferably with an upper grating 150) could also beprovided on the outer body section 166, with the chute 148 preferablybeing spaced some distance away from the conveyor outer end 106 so thatthe chute 148 does not open above the region where the flights 112 arestill traveling to the front of the conveyor body 102. The grating 150need not take the form of parallel bars 152, and could (for example)take the form of bars 152 defining a mesh. The bars 152 need not beround, and could (for example) be slat-like, preferably oriented topresent a narrow edge at the top of the chute 148 to better break up anyclumps of material.

The tensioner 180 can operate to adjust the location of the outer wheel118 along the conveyor body 102 by mechanisms other than a screw 186,e.g., via a ratcheting mechanism, or via a piston or other member drivenby a spring (or via hydraulics, pneumatics, etc.) to apply tension.Alternatively, the wheel-bearing tensioner 180 might simply be moved toa desired location which yields the desired tension in the belt 114, andmight then be bolted, wedged, or otherwise affixed in place.

Apart from the foregoing features, the sweep conveyor 100 mightincorporate features found in one or more of the patents listed near thebeginning of this document, and/or in patents cited in (or citing to)these patents.

In summary, the sweep conveyors encompassed by this patent are notlimited to the various versions described above, but rather are limitedonly by the claims set out below. Thus, this patent encompasses alldifferent versions of the sweep conveyor that fall literally orequivalently within the scope of these claims.

What is claimed is:
 1. A sweep conveyor including: a. a conveyor body having a conveyor length extending between opposing conveyor first and second ends; b. a pair of wheels including: (1) an inner wheel at or adjacent to the conveyor first end, and (2) an outer wheel at or adjacent to the conveyor second end; c. an endless belt riding on the inner and outer wheels; d. flights spaced along the belt, each flight having a length protruding from the belt between: (1) a flight inner end at which the flight is affixed to the belt, and (2) an opposing flight outer end; e. a roof extending over a first set of the flights; and f. a grating extending: (1) from the roof, and (2) over a second set of the flights, whereby material falling through the grating falls between the flights.
 2. The sweep conveyor of claim 1 wherein: a. the conveyor body is formed of two or more body sections adjacently arrayed end-to-end along the conveyor length, b. the body sections include: (1) an inner body section: (a) situated at or adjacent to the conveyor first end, and (b) wherein the inner wheel is situated on the inner body section; (2) an outer body section: (a) situated at or adjacent to the conveyor second end, (b) wherein the outer wheel is situated on the outer body section, and (c) wherein the flights spaced along the belt riding on the outer wheel are exposed from both the front and the bottom of the outer body section; (3) at least one intermediate body section situated between the inner body section and the outer body section.
 3. The sweep conveyor of claim 2 wherein: a. the inner wheel is movably situated on the inner body section, and/or b. the outer wheel is movably situated on the outer body section, whereby moving the inner or outer wheel adjusts the distance between the inner and outer wheels, and thereby adjusts tension in the belt thereon.
 4. The sweep conveyor of claim 2: a. further including a forward inner wall extending along the conveyor length, wherein: (1) a space defined forwardly of the forward inner wall defines a sweep area, and (2) a space defined rearwardly of the sweep area defines a return area; b. wherein at least one of the body sections includes: (1) at least a portion of the roof, and (2) at least a portion of the grating.
 5. The sweep conveyor of claim 4 wherein the roof further extends over at least a portion of the sweep area.
 6. The sweep conveyor of claim 1 wherein the grating is defined by spaced bars.
 7. The sweep conveyor of claim 1: a. further including a forward inner wall extending along the conveyor length, wherein: (1) a space defined forwardly of the forward inner wall defines a sweep area, and (2) a space defined rearwardly of the sweep area defines a return area; b. wherein the roof extends over a portion of the sweep area, and c. wherein the grating also extends over a portion of the sweep area, with the roof and grating being adjacently situated along the conveyor length.
 8. The sweep conveyor of claim 1 further including: a. a forward inner wall extending along the conveyor length, wherein: (1) a space defined forwardly of the forward inner wall defines a sweep area at which the flights are exposed from both the front and the bottom of the sweep conveyor, and (2) a space defined rearwardly of the sweep area defines a return area; b. a rearward inner wall extending along the conveyor length, c. a rearward outer wall extending along the conveyor length, wherein the return area is situated between the rearward inner and outer walls, and d. a rear floor extending between the rearward inner and outer walls beneath the return area.
 9. The sweep conveyor of claim 1 further including a flexible flange extending downwardly below the conveyor body along the conveyor length, whereby as the conveyor body travels along a floor, the flange rides along the floor.
 10. The sweep conveyor of claim 9: a. further including a forward inner wall extending along the conveyor length, wherein: (1) a space defined forwardly of the forward inner wall defines a sweep area, and (2) a space defined rearwardly of the sweep area defines a return area; b. wherein the flexible flange descends from the forward inner wall.
 11. The sweep conveyor of claim 9 further including: a. a rearward outer wall extending along the conveyor-length rearwardly of the belt and the flights thereon, and b. an elongated plate sandwiching the flexible flange against the rearward outer wall.
 12. The sweep conveyor of claim 1: a. further including: (1) a forward inner wall extending along the conveyor length, wherein: i. a space defined forwardly of the forward inner wall defines a sweep area, and ii. a space defined rearwardly of the sweep area defines a return area; (2) a rearward inner wall extending along the conveyor length, wherein the rearward inner wall forwardly bounds the return area; b. wherein the conveyor body is formed of two or more body sections adjacently arrayed along the conveyor length, each of the body sections including: (1) a portion of the forward inner wall, and (2) a portion of the rearward inner wall, b. one of the body sections bears a tensioner translatably received between the forward and rearward inner walls, wherein the tensioner bears one of the inner and outer wheels thereon.
 13. The sweep conveyor of claim 12 wherein a screw extends between and engages: a. the body section bearing the tensioner, and b. the tensioner, whereby rotation of the screw adjusts the location of the tensioner relative to the body section bearing the tensioner.
 14. The sweep conveyor of claim 12 wherein the tensioner extends between: a. a tensioner wheel end bearing one of the inner and outer wheels, and b. an opposing tensioner adjustment end having a screw extending therefrom, the screw being rotatably mounted with respect or one or more of the forward and rearward inner walls of the body section bearing the tensioner.
 15. The sweep conveyor of claim 1 wherein each flight is: a. rigid for a major portion of its length extending from the flight inner end, and b. flexible for a portion of its length extending from the flight outer end.
 16. The sweep conveyor of claim 1 wherein each flight: a. is formed of a plate of flexible material, and b. is fixed to a rigid leg extending outwardly from the belt, the rigid leg extending for a major portion of the flight's length extending from the flight inner end.
 17. The sweep conveyor of claim 1 wherein at least one of the inner and outer wheels is movable along the conveyor length, whereby one or more of the wheels adjusts the tension in the belt thereon.
 18. A sweep conveyor including: a. a conveyor body having: (1) a conveyor length extending between opposing conveyor first and second ends, (2) conveyor front and rear sides extending along the conveyor length, (3) a sweep area defined along the conveyor front side, (4) a grating atop at least a portion of the conveyor front side, and over the sweep area, (5) a return area extending along the conveyor length rearwardly of the sweep area, and (6) a roof atop at least a portion of the conveyor rear side, and over the return area; b. inner and outer wheels oriented to rotate about at least substantially vertical axes, wherein: (1) the inner wheel is situated closer to the conveyor first end than to the conveyor second end, and (2) the outer wheel is situated closer to the conveyor second end than to the conveyor first end; c. an endless belt riding on the inner and outer wheels; d. flights spaced along the belt and within the sweep and return areas, each flight having a length extending from the belt between: (1) a flight inner end at which the flight is affixed to the belt, and (2) an opposing flight outer end.
 19. The sweep conveyor of claim 18 wherein: a. the conveyor body is formed of two or more body sections adjacently situated along the conveyor length, and b. at least two adjacent body sections are hingedly connected, whereby the hingedly connected body sections pivot with respect to each other in vertical planes.
 20. A sweep conveyor including: a. a conveyor body: (1) having a conveyor length extending between opposing conveyor first and second ends, (2) having a forward inner wall extending along the conveyor length, wherein: i. a space defined forwardly of the forward inner wall defines a sweep area, and ii. a space defined rearwardly of the sweep area defines a return area; (3) wherein the conveyor body is formed of two or more body sections adjacently situated along the conveyor length, each of the body sections including a portion of the forward inner wall, (4) at least two adjacent body sections are hingedly connected, whereby the hingedly connected body sections may pivot with respect to each other in vertical planes, b. a pair of wheels oriented to rotate about at least substantially vertical axes, the wheels including: (1) an inner wheel at or adjacent to the conveyor first end, and (2) an outer wheel at or adjacent to the conveyor second end; c. an endless belt riding: (1) on the inner and outer wheels, and (2) around the forward inner wall; d. flights spaced along the belt and within the sweep and return areas, each flight having a length protruding from the belt between: (1) a flight inner end at which the flight is affixed to the belt, and (2) an opposing flight outer end.
 21. The sweep conveyor of claim 20 further including a rearward inner wall extending along the conveyor length, wherein: a. the rearward inner wall forwardly bounds the return area, and b. each of the body sections includes a portion of the rearward inner wall.
 22. The sweep conveyor of claim 20 wherein the hingedly connected body sections include lengths of flexible barrier material joined between the hingedly connected body sections.
 23. The sweep conveyor of claim 21 wherein: a. the walls extending along the conveyor length further include a rearward outer wall rearwardly bounding the return area, and b. the hingedly connected body sections include: (1) a set of hinge plates connected to the rearward outer walls of the body sections outside the return area, the hinge plates being pivotally pinned together, and (2) a set of hinge plates connected to the forward inner walls of the body sections outside the sweep area, the hinge plates being pivotally pinned together.
 24. The sweep conveyor of claim 23 wherein each set of hinge plates defines three or more adjacent ears with a pin extending therebetween.
 25. The sweep conveyor of claim 20 wherein the conveyor body includes: a. a roof extending the sweep area, and b. a grating extending adjacent the roof and above the sweep area. 